Eyepieces for Astromaster 130

[Pawel]

Astromaster  telescope 130 mm tube what lens should I use to see the planets like saturn with its own ring apparently can I see trough that tele scope similar objects and planets in night sky 

Anyone can help ? 

 

 

 

[Putaendo Patrick]

I believe your telescope has a focal length of 650mm - this is important to calculate the magnification a particular eyepiece will give. The Astromaster usually comes with 20mm and 10mm eyepieces which will give x32.5 and x65 magnifications.

You should be able to see the moons of Jupiter and a suggestion of Saturn's ring at x65. However, to see more detail magnifications between x100 and x200 would be useful - a lot depends on atmospheric conditions on the night, sometimes increasing the magnification only increases a blur and you don't get better views.

A 6.5mm eyepiece will give you x100 which is very possible with your telescope. 3.25mm would in theory give you x200, but I reckon this is pushing it for the Astromaster 130. A 5mm eyepiece would give a very useful x130.

An alternative is to use a Barlow which effectively increases the magnification of an eyepiece. A x2 Barlow for example will double the magnification. Remember, however, the supplied eyepieces you probably already have are not the best quality. Combining these with a cheap Barlow will not work well.

If you want to give us an idea of your budget, I'm sure you'll receive many suggestions for suitable brands.

[MarsG76]

I agree with the above statement. Some of the nicest views I saw of Saturns rings on a semi clear night were at about 184X. It was stable and clear, so for your scope if it is 650mm focal length use either a 3.5mm eyepiece or a 7mm eyepiece with a 2X barlow, but a 5mm EP is a good midpoint.

 

[Lance Bridwell]

I have a Hyperion 8mm to 24mm zoom eyepiece, is there an easy way to change the eyecups?.

[Putaendo Patrick]

The eyecups fit over an M43 thread and can be easily removed.

Replacements are available, for example http://www.teleskop-express.de/shop/product_info.php/language/en/info/p7765_Baader-2454651---M43-thread-protection-ring-and-eye-cup.html  in Germany - but I've no idea of distribution in the US. Presumably any other style of eyecup of the same diameter would fit easily.

[ronin]

For the rings of \Saturn you need a sharp image as well as one of sufficent size, so be a little careful of bigger is better. For the Cassini division you need sharp. My best view was at 125x in a long refractor. I am not sure what the focal length of your scope is - I have the idea that there may be some at around f/8 and that the mirror may be spherical.

I would suggest that for now you limit yourself to a magnification the same as the mirror diameter (have a reason for this) so around the 130x area. For this you need an eyepiece of the same focal length as the f number of the scope. So if it is an f/5 scope you want a 5mm eyepiece if it is around f/8 then you need an 8mm eyepiece. This means I do not need to know the focal lengh specifically to suggest an eyepiece focal length, just get one as per the f number and you have about 130x.

Not sure which type to suggest a plossl should work but if f/5 it is getting close to their best operation. Plossl's maybe a GSO/Revelation for a bit more the Vixen NPL. After that really it is the standard BST Starguiders, or the Celestron X-Cel LX's. This brings youto the £50-60 mark and I doubt that at this time you want to spend more.

By the way Jupiter appears in the evening/night sky next year - think about March, Saturn is later in the year, Not many planets around at present. Jupiter is visible around 4:00 to 5:00 in the morning presently if you want to get up and stand outside in the cold.

[LukeSkywatcher]

Your scope should feel right at home and give good views with a wide range of eyepieces. By this i mean, you dont need to invest in expensive eyepieces. It will happily be able to use Plossl design eyepieces. Some are better than others but essentially they are all roughly about 30-40 quid.

I personally find (as other do) an 8mm eyepiece is just about right for planets. 5mm is also good. If using 8mm, you may use a 2x barlow which gives you 4.5mm. This could be pushing the scope limit a bit......but not by much and it works (i have a similar spec scope).

My point here is you really dont have to spend loads of cash on quality EP's....simply because the scope will be/is very "forgiving". I love the Vixen NPL range of eyepieces (EP's), but some people dont like them because of the small exit pupil (distance between eye and eyepiece needed to be able to comfortably see anything).

P.S.~to enjoy viewing the planets (the inner ones anyway), you dont really need to use very high magnification such as 5-8mm. I find some of the best views i have seen come with 15-25mm. Obviously you wont see as much detail but its not ALWAYS about detail. I do like to sit and watch Jupiter and its moons from a widefield view and see the moons dance around the planet.

 

Edited December 6, 2016 by LukeSkywatcher

[David Harding]

HI. I've just bought this Astromaster 130. It's great but needed more magnification to at least see Saturn's rings, so I searched and found this thread founding all my answers, and such good answers! Thanks to all.

Will be asking for advise since I am a totally beginner.

Best

[Louis D]

I'm glad someone got some use out of this old thread.  @Pawel only posted once and hasn't even visited since that first day he/she joined and posted, so didn't even ever read all the responses.

[ips138]

I got the Astromaster EQ and also found the post. Much appreciated the discussion and experiences shared. Found it very useful

I am settling for the BST EPs. Had already seen recommended and this gave me more confidence for the quality/budget. Now, Im just wrestling HOW many....
Ideally, the 5,8,18 and 25 alongside the 2x barlow. The 3.2 would be pushing this scope. and the 12, 15 not as useful.

The question I'm left at this time is if the 5 would be much better quality than the 8+barlow or if I can skip it. but still have detail. Any thoughts? Thanks.

[Ricochet]

On 14/09/2023 at 23:09, ips138 said:

Ideally, the 5,8,18 and 25 alongside the 2x barlow. The 3.2 would be pushing this scope. and the 12, 15 not as useful.

Actually, I think the 12 is probably the most useful for an F5 scope like yours as it gives an exit pupil of 2.4mm, which is perfect for DSOs. Above this you want a high power star cluster eyepiece at 12/1.4, so the 8mm, and a low power wide field/finder at 12x2 so the 25. An exit pupil of 0.8mm is acceptable for a high power planetary eyepiece and with a small scope you'll want to push the magnification a bit so a 2X barlowed 8mm (8/2=4) giving approximately 163X should work well. This will give you the range of focal lengths of 4, 6, 8, 12, 25 and you can hold off buying the 5 until you determine if you need something between 4 and 6. 

The only fly in the ointment with this plan is the performance of the 25mm at F5. Optimal performance of the Starguider eyepieces appears to be achieved when using a scope with a focal ratio in the order of eyepiece focal length/2, or higher. The 12 should still be ok but the 25 will be increasingly astigmatic towards the edges (stars look like seagulls). Getting a better corrected eyepiece at this focal length is more expensive. The cheapest well reviewed option that comes to mind is the 24mm Stellalyra UFF, but it is double the price and weight of a Starguider.